The man had visitation rights but only in the presence of another person, the official said, adding that this was the first time he had brought the children home to his apartment on the second floor of a four-storey building without a third party being present.

He remained in custody late Sunday and was to be presented to a prosecutor on Monday when he was expected to be charged.

Police were also questioning his ex-wife, notably to learn more about “the legal framework of the children’s visits to their father”.

“We understand that a British national has been arrested in France,” a Foreign Office spokesman told AFP. “We are in contact with the French authorities and we await the outcome of their investigation.”